Field of the Invention
The present invention relates to a device and a method for manufacturing welded shaped steel by laser-welding a web member and flange members for weld-bonding with laser light as a heat source.
Description of the Background Art
Patent Documents 1, 2 describe methods for manufacturing welded H-shaped steel by laser-welding a web member and flange members for weld-bonding. In the described methods, a web member and two flange members supplied in such a manner that they are arranged in an H shape are laser-welded at predetermined welding positions for weld-bonding.
When a web member and flange members are laser-welded for weld-bonding, it is required that butt-positions of the web member butting against the flange members be set precisely under the constraint that a laser irradiation position is set and a laser beam spot is as small as about 0.6 mm in diameter. The butt positions of the web member butting against the flange members deviate from appropriate positions if the supplied web member is warped or the supplied web member is slanted with respect to the flange members. In this situation, there are probabilities that laser irradiation would not sufficiently melt a matrix and result in insufficient weld-bonding in strength, and that a completed product would have deficiencies in shapes or dimensions. When the web member and the flange members are laser-welded for weld-bonding, therefore, it is required that the butt positions of the web member butting against the flange members do not deviate from appropriate positions.
Patent Document 3 describes a device for high-frequency resistance welding three plate members, which are obtained by unrolling their respective coils and arranged together in an H shape, for weld-bonding. The described device is provided with a supporting device configured to support both surfaces of the web member. This supporting device is constituted by endless belts caused to travel by following travel of the web member conveyed in a line direction. In Patent Document 3, it is described that the supporting device is capable of entirely retaining the web member at a welding portion so that the web member can be prevented from escaping in a thickness direction thereby avoiding welding deficiencies.